The present disclosure relates to the management of real storage, and more specifically, to reserving fixed page areas in real storage increments using target request amounts.
Many computer systems utilize a large frame area (LFAREA) to support the storage of large pages, such as pages equal to or larger than 1 megabyte (MB). The LFAREA includes one or more online real storage address increments. Currently, the real storage increments range from 64 MB to 2 gigabytes (GB) depending on the processor machine model. The number of pages to be reserved is requested via an LFAREA system parameter (e.g., LFAREA=24M is a request to reserve 24 1 MB pages in the LFAREA). Reserving a desired number of pages can be accomplished by scanning the real storage increments and selecting the real storage increments that are online and available until the requested amount is achieved. In many current systems the amount of storage that can be reserved in the LFAREA is limited to 80 percent of the online storage minus 2 GB.
As the page size of large pages used by computer systems increases, the page size may become larger than the real storage increments used by the computer system. As a result, the selection process becomes more complex since it must find enough contiguous online and available real storage increments for each page area that is to be reserved. In addition, the selection process can be further complicated by gaps in storage increments caused by offline storage increments.